Saturday, April 25, 2009

Passive solar design

Today we are participating in the Sustainability Fair at the Palmyra Cove Nature Park, just 1 mile down river from our office.
We have a table set up and are going offer free architectural consultation and answer any questions  about how to make homes greener, and sustainable habits  to get into.

Passive Solar Design

  A simple overhang  can be positioned over a window to allow warmth from the Sun into the house in the Winter, and shade the window from the Sun during the Summer months. The length of the overhang can be calculated from Sun angle charts. These show where the Sun is in relation to your part of the planet at a certain time of year. The Sun is higher in the sky during the Summer months and is highest at the Summer Equinox June 21, and lowest at the Winter Equinox on December 21, as shown in the drawing above. The drawing in a sketch of a project that we did a passive solar analysis for. It shows how much shade, and sunlight, will be let into the window with the overhang being a certain length. The longer the overhang the less direct sunlight you will receive in the Summer, which will keep down solar gain, it will not effect the amount of sunlight received in the Winter, because the Sun is lower on the horizon then.
Overhangs can be retrofitted to an existing house, but if you are in a colder climate make sure that the overhang is designed to hold the weight of the snow loads. This is only one step to take toward creating a zero energy house.
Let nature work for you. Shading is very important, it will block the direct sunlight during the warmer months and allow the rays in to warm the space during winter, when the Sun is lower on the horizon.
A Sugar Maple tree is a good candidate for shading, it fills out during the Summer and grows fast, so if you have to plant from new, it should reach 12 to 15 feet in about 3 or 4 years.

A Sugar Maple
This tree took about 10 years to grow, it was 6' high when it was planted. It lets in all of the Sun during the Winter and shades the whole house during the Summer. Overhangs are a much quicker solution.
The shading works very well, this was taken at the start of Autumn.

1 comment:

  1. Our optimistic planting just got us another six inches of snow. Pfffffffffft.